The map below is from XMetMan and produced with his permission.

It shows total rainfall from the synoptic observations (so not the official morning rainfall measurements, but I'd say within 99%) during January.

Capel Curig comes out as wettest with Aberdeen Dyce being the driest place during the month.

Notice too how wet western and Northern Ireland as well as western Scotland and southwest England were. Some eastern counties of England were dry too tih only 36.4mm at Boulmer.